Hand-screw



(No Model.)

A. H. GEORGE.

HAND SGREW.

No. 431,719. Patented July 8, 1890.

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Tn: NORRIS versus cm. Pnowuruo, msnmr-mn, n. c.

UNITED STATES PATENT OFFICE.

ADAM HENRY GEORGE, OF PASSAIC, NEIV JERSEY.

HAN D-SCREW.

SPECIFICATION forming part of Letters Patent No. 431,719, dated July 8,1890.

Application filed July 29; 1889. filerial No. 319,103. (No model.)

To all whom it may concern:

Be it known that I, ADAM HENRY GEORGE, of Passaic, county of Passaic, inthe State of New Jersey, have invented a certain new and Improved HandVise Clamp, technically known in the joiners trade as hand-screw, ofwhich the following is a specification.

My clamp or hand-screw is intended more particularly for joiners use inholding together pieces of freshly-glued wood; but it may be used forvarious other purposes, if required. I have in a patent issued to me,dated January 10, 1888, No. 376,191, described a clamp for similarpurposes having springdogs engaging and releasing two ratchet-bars, onetraversing the middle and the other the baclr end of the clamp. Thesewould allow the aws to be rapidly changed to wide extents. A lever andtoothed bar operated at the back end, applied after the jaws had been adusted to the nearly-right position, brought the clamping ends of thejaws together with the required force. My present invention employs thesame general arrangement. The ratchet-bars may be made cheaply andperfectly in the form of screws, and such will serve the same purpose ifthe dogs be made with engaging parts adapted therefor; also, thehandling of the device and the operation of the lever maybe greatlyfacilitated by provlding a handle on the upper jaw extending out underthe hand-lever. I use such handle and also such screws and dogs withteeth properly inclined to match the inclined positions of thescrew-threads. I provide each dog with two or more such teeth aproperdistance apart to engage a corresponding number of the threads of thescrew at the same time. This gives amore reliable hold. I apply a springwhich raises the hand-lever automatically so soon as it is set free.

The accompanying drawings form a part of this specification andrepresent what I consider the best means for carrying out the invention.

Figure l is an edge view, and Fig. 2 a top plan, of my improved clamp.Figs. 3 and 4 are.details, which will be more particularly hereinafterreferred to by reference-letters.

Similar letters of reference indicate correponding parts in all thefigures.

A and B are the two jaws, each faced with wood, as in my previouspatent.

C and D are screws finished in a lathe,with V-shaped threads, eachsquare on its lower cated. The screw 0 traverses the middle and thescrew D the back end of the jaws.

E E are dogs actuated by spiral springs G and engaging with the screw D.Each has a wide engaging-face hollowed to match the side of the screwand provided with two or more engaging-teeth e, arrangedto engage two ormore threads of the screw D at the same time and to let go of both whenthe dogs are properly turned against the force of the springs G. I I arecorresponding dogs actuated by springs J, engaging the screw 0. Theacting faces of these dogs I are hollowed to match against the screw 0,and each is equipped with two or more teeth 2', properly inclined andspaced, to engage two or more threads of the screw 0 at the same time.The hand-lever H, by which the final strain is applied to the clamp, isequipped with a spiral spring W, which exerts a gentle force, tending toraise the lever. In relaxing the clamp the lever H and its attachmentsrise so soon as the teeth of the ratchet-bar M are disengaged fromtheirhold on the jaw B. This instantly throws open to a slight extentthe front ends, the effective ends of the jaws.

B* is a handle cast integral with the jaw B, extending out under thelever H, as shown. In the last part of the motion to tighten the clampthe operator takes the lever H and the handle B* together in the hand,and by forcibly closing the hand operates the lever with great force.

0' is a thumb-head on the screw 0. After the clamp is in place, beforeoperating thelever H, the screw 0 is revolved by acting on its head C,so as to take up all slack. Then the turning of the lever H and theengagement of its locking-rack m with a suitable lip on the jaw Bcompresses and holds the device with great force.

The jaws may be faced with wood,as in my previous patent.

Modifications may be made without departing from the principle orsacrificing the adside and inclined on its upper side, as indivantagesof the invention. I can use more than two engaging-teeth e or 2' on eachdog E or I. There is alimit to how wide the acting face of each dog maybe. It is important to have a little looseness to allow for the slighttilting motion to which the jaws are subjected in tightening orreleasing.

I claim as my invention 1. In a clamp,,the lever II, spring WV, andratchet-bar M, in combination with the jaw B, having the handle 13*, andWith the jaw A and adjustable connecting means, arranged to serve asherein specified.

2. In a clamp, the screws 0 D, serving as ratchet-bars, with means 0 forrevolving one of them, the jaws A B, and the dogs E I, with ADAM HENRYGEORGE.

WVitnesses:

CHAS. F. BARTER, WM. HUTCHISON.

